Setup problem?

Hi.
I've installed a GW7 system on an OES (Linux).
All seems fine, but...

1) Is impossible to send mail outside the gw domain (i.e. internet) without
adding the prefix gwia to the recipient address.
The "foreign" addresses are not recognized; I made a test with an address
such "test-test" and the result is the same.

2) No way to connect to the system using standard IMAP/POP clients

3) SMTP sendings from clients above are refused with an error like "non
existent user", even if I put on the relay host field in GWIA.

Any clues?

Thanks...